In the field of warming devices utilizing heat generation by oxidation of iron powder, incorporation of capsaicin or menthol into warming devices is known. For example, patent literature 1 below describes a warming device including an air permeable bag containing a heat generative material capable of heat generation on contact with air and a plaster layer on the skin contact side of the bag, the plaster layer containing an effective ingredient of plaster, such as a capsicum extract or l-menthol.
Patent literature 2 below discloses a warming sheet including a pressure sensitive adhesive layer and a heat generating layer containing a heat generating substance, the pressure sensitive adhesive layer containing heat generative gel comprising a polyhydric alcohol and a polymer soluble or swellable in the polyhydric alcohol. The literature mentions that the heat generative gel may contain capsicum and l-menthol.
Apart from warming devices, it is known that a medicated composition for external use, such as an external preparation or a patch, may contain a warming sensate component having a 4-hydroxy-3-methoxyphenyl group and a warming sensate component having a vanillylamide group, such as capsaicin (see patent literature 3 below).